JP2007326330A - Mold for molding composite optical element, and composite optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding a composite optical element which can be used for improving releasing properties between a molded resin and the mold for molding, in comparison with a conventional replica molding, and for improving efficiency of production and reducing the cost for the element, and to provide the composite type optical element. <P>SOLUTION: In the mold for molding the composite optical element having a molding face for transferring an optical shape 19 onto a photo-curable resin, the photo-curable resin 12 pressed and filled on the molding face by a glass substrate 13 is photo-cured, and the cured resin with the glass substrate is released from the molding face, there exists a projecting shape part 18 with a height of 70-90% of the resin thickness of the photo-curable resin out of an optically effective molding face on the molding face. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding die for a composite optical element and a composite optical element. In particular, the present invention relates to a molding die for a composite optical element and a composite optical element in so-called replica molding, in which a molding surface is transferred to a photocurable resin by a molding die to obtain an optical surface shape.

Conventionally, as one of the molding technologies for composite optical elements such as diffractive optical elements and aspherical lenses, there is a replica molding technology that excels in large area moldability and high transferability, and is suitable for mass production due to the ease of the molding technology. Are known.
In this replica molding technique, a photocurable resin is dropped onto a mold surface having a reverse shape of a desired optical shape, and a lens blank as a substrate is crimped and spread out from above to form a desired shape. The light curable resin is cured by irradiating light from the light source. Then, by releasing the cured resin together with the lens blank, the shape on the mold is transferred to the cured resin for molding.
In such replica mold release, a part of the cured resin adheres to the surface of the mold, and the optical fine shape such as the diffractive optical element is deformed or damaged by the stress at the time of mold release. Therefore, it is difficult to release the molded product easily and accurately. Also, in the photo-curable resin of the molding material, there are not a few materials with high adhesion to the mold due to the recent diversification of the composite material, and similarly, the molded product can be easily and accurately released. difficult.

In the past, in order to improve mold release properties in replica molding for molding a composite optical element, for example, a technique of applying a mold release agent to the mold surface or a technique of adding a mold release agent to a molding resin material Etc. are known. Many replica mold release methods or molds for improving mold release have been proposed.
For example, in Patent Document 1, a method is provided in which a concave / convex surface is provided on the outer peripheral portion of the optical effective diameter of the molding die, the molding resin is filled up to the outer peripheral portion of the concave / convex surface, and the molding is cured, thereby reducing the release force at the time of releasing Has been proposed.
In Patent Document 2, there is a method of forming a V-groove in the outer peripheral portion outside the optical effective diameter of the mold, reducing the adhesion between the resin material and the mold at the mold release start point, and facilitating the mold release. Proposed.
Moreover, in patent document 3, the protrusion by which outer peripheral part resin thickness is adjusted outside the optical effective diameter of a shaping | molding die is provided, the dent by the surface tension in the resin layer side surface center part is made small, and this dent part is optically effective. A configuration of a mold that does not protrude into the diameter has been proposed.
Further, in Patent Document 4, the angle θ between the outer periphery of the optical effective diameter of the molding die that contacts the end portion of the molding resin and the central axis of the molding die is set to 15 ° <θ <45 °, whereby the shape of the molding resin end portion is changed. A method of controlling and releasing from the outer peripheral portion without a defect has been proposed.
Japanese Patent No. 3092964 Japanese Patent Laid-Open No. 5-220773 Japanese Patent No. 3228613 Japanese Patent No. 3184777

By the way, in the mold release process of the replica molding technology for composite optical elements such as aspherical lenses and diffractive optical elements, it is difficult to avoid any deformation or loss of the optical shape due to stress at the time of mold release.
The mechanism of mold release in replica molding is to generate an interface crack by applying a load in the vertical direction or shear direction to the outer peripheral edge of the interface between the molding resin and the mold, and this interface crack is transferred to the inner molding surface. The mold release is performed by making it proceed continuously. The smaller the release stress applied to the interface during this release process, the better. In particular, when a large release stress is applied, the optical curved surface of the aspherical lens, the grating surface of the diffractive optical element, or the like is deformed or lost. Needless to say, these deformed portions and missing portions significantly deteriorate the optical performance of the composite optical element.

However, the above-described replica molding technique in the conventional example is not always satisfactory in improving mold release properties.
For example, in a method in which a mold release agent is applied on the mold surface to reduce the adhesion at the interface between the mold and the molding resin, dripping due to liquid application or uneven film thickness due to surface tension is extremely This will distort the optically curved surface and fine shape on the precisely processed mold surface.
In addition, in the method of adding a mold release agent to the molding resin itself, the influence of deterioration of the optical properties such as deterioration of environment resistance and refractive index of the molding resin has been confirmed, and as an optical material for molding a composite optical element, It is not preferable.
In Patent Document 1, an uneven surface is provided on the outer periphery of the optical effective diameter of the mold so as to release the mold. It cannot be improved.
Also in Patent Document 2, a V-groove is provided on the outer periphery of the outer periphery of the optical effective diameter of the mold so as to release the mold. The sex cannot be improved further.
Further, in Patent Document 3, a protrusion is provided on the outer periphery of the optical effective diameter of the mold so as to release the mold. However, since the position where the molding resin is filled is not appropriate, Curing shrinkage cannot be controlled and the releasability cannot be further improved.
Further, in Patent Document 4, the shape of the end portion of the molded resin is determined by setting the angle θ between the outer periphery of the optical effective diameter of the molding die in contact with the end portion of the molded resin and the central axis of the molding die to be 15 ° <θ <45 °. It is controlled and released. However, even in this case, since the stress distribution in the molding resin at the time of mold release is not appropriate, the mold release property cannot be further improved.

  Further, in these conventional examples, since the shape control of the outer peripheral end portion of the molding resin is not sufficient, a large amount of resin residue is generated on the molding die surface due to the cohesive failure of the cured resin at the time of mold release. When this phenomenon occurs at the production site of composite optical elements, the operator must wipe off the residual resin adhering to the mold surface every time, which not only reduces productivity and significantly increases costs. Further, the durability of the mold is lowered. It goes without saying that a composite optical element that has been released due to large cohesive failure results in a defective product.

  In view of the above problems, the present invention can improve the mold releasability between a molding resin and a mold as compared with conventional replica molding, and can improve production efficiency and reduce costs. An object of the present invention is to provide a molding die and a composite optical element.

In order to solve the above problems, the present invention provides a molding die for a composite optical element and a composite optical element configured as follows.
The present invention includes a molding surface for transferring an optical shape to a photocurable resin, photocuring a photocurable resin press-filled on the molding surface with a glass substrate, and then curing the cured resin to the glass substrate. In addition, in the molding die for molding the composite optical element by releasing from the molding surface, the height of the resin thickness of the photocurable resin is 70% or more and 95% or less outside the optically effective molding surface of the molding surface. It has the convex-shaped part which has. In the molding die for a composite optical element according to the present invention, the convex portion is disposed at one point or a plurality of points outside the optical effective molding surface, or at the entire outer periphery outside the optical effective molding surface. It is characterized by.
The composite optical element of the present invention is characterized by being molded using the composite optical element molding die described above.
The composite optical element of the present invention is a diffractive optical element or an aspheric lens.

  According to the present invention, compared with the conventional replica molding, the mold release property between the molding resin and the molding die can be improved, and the production of the composite optical element that can improve the production efficiency and the cost can be achieved. Mold and composite optical elements can be realized.

  The above configuration can achieve the above-described problem of the present invention, which is based on the following knowledge of the present inventor. That is, by setting a convex portion having a height of 70% or more and 95% or less of the resin thickness of the photocurable resin outside the optical effective molding surface (outside the optical effective diameter) of the molding surface, photocuring due to curing shrinkage. This is because it was found that the inward flow of the functional resin is prevented and the releasability is improved.

Next, these will be described in more detail.
1 and 2 are schematic views for explaining a curing process of a photo-curing resin in replica molding.
In FIG. 1, the filled resin surface 4 in which the uncured photocurable resin 2 pressed and filled between the mold 1 and the lens blank 3 comes into contact with the atmosphere is exposed outside in the uncured state immediately before filling and before light irradiation. A convex shape that faces is formed. The convex shape of the outer peripheral end is a surface state such as the water repellency of the mold 1 or the lens blank 3, or the viscoelasticity of the photo-curing resin 2 before curing used, and changes with time due to gravity or ambient temperature. It is formed according to conditions.
Next, as shown in FIG. 2, the cured curable resin 2 ′ in which the cured photocurable resin 2 ′ is in contact with the atmosphere by irradiating the light of the light curing light source 5 to the uncured photocurable resin 2 The surface 4 'forms a concave shape facing inward.
This is because the curing shrinkage represented by the arrow (↑) shown in the photocurable resin 2 ′ after curing is concentrated at the interface between the photocurable resin 2 before curing and the atmosphere. That is, curing shrinkage occurs only slightly at the interface between the pre-curing photocurable resin 2 and the mold 1 or the lens blank 3 with relatively high interfacial adhesion energy, and curing with relatively low interfacial adhesion energy. This is due to the concentration occurring at the interface between the previous photocurable resin 2 and the atmosphere.
In the curing process shown here, the lens blank 3 is held at equal intervals with respect to the mold 1 by the lens blank holding member 7, but is cured at the interface between the photocurable resin 2 and the mold 1 before curing. If the shrinkage works, a peeling phenomenon of the interface called so-called sink occurs.

On the other hand, curing shrinkage that occurs at the interface between the photocurable resin 2 and the lens blank 3 before curing occurs as distortion of the lens blank 3, but the distortion decreases as the lens blank 3 is thicker or its elasticity is smaller. .
3, 4, and 5 are schematic diagrams for explaining the mold release process of the composite optical element in replica molding.
Each figure shows the filling and curing that the filling cured resin surface 4 ′ at the outer peripheral portion of the interface composed of the filled cured photocurable resin 2 ′ and the mold 1 that generates an interface crack at the time of mold release becomes the molding die surface. The cross section in each angle next to angle (theta) represented by the resin side is represented.
That is, it represents a cross section of the angle θ of 0 ° <θ <90 °, θ = 90 °, 90 ° <θ <180 °.

FIG. 3 is a cross section in which the filled cured resin surface 4 ′ is formed in a concave shape facing inward (0 ° <θ <90 °), and the release force F shown in the figure is applied to the end of the lens blank 3. The progress of the release crack when the load is applied vertically is indicated by a broken line arrow 6 in the figure.
The stress distribution applied to the concave filling resin surface 4 ′ by the releasing force F is the starting point of the release crack progression 6 slightly away from the interface between the mold 1 and the cured photocurable resin 2 ′. Is the largest.
There, about three times as much stress is applied as compared with that of the concave central portion of the filled cured resin surface 4 ′.

A specific example of a schematic diagram of the mold release process of FIG. 3 is shown in FIG.
In FIG. 6, in the cured photocurable resin 2 ′ having a resin thickness of 50 μm and a filled cured resin surface 4 ′ formed in a concave shape with a curvature radius of 25 μm, the vertical direction 1.0 [ When a release force of N / mm ² ] was applied, stress concentration was confirmed at the next position.
That is, stress concentration was confirmed at a position of 15 μm in the horizontal direction and 4 μm in the vertical direction from the contact interface between the filling cured resin surface 4 ′ and the mold 1.
This indicates that there is a high possibility of cohesive failure of the resin, in which the release crack occurs on the filled cured resin surface 4 ′ rather than the contact interface between the filled cured resin surface 4 ′ and the mold 1. In the cohesive failure of the filled photocurable resin 2 ′ after curing, not only a larger mold release force is required at the time of mold release, but also a residual resin is left on the mold 1.

  FIG. 4 is a cross section in which the filling cured resin surface 4 ′ forms a vertical surface with respect to the mold 1 (θ = 90 °), and the release force F shown in the figure is applied to the end of the lens blank 3. The progress of the release crack when the load is applied vertically is indicated by a broken line arrow 6 in the figure. The stress distribution applied to the vertical filling cured resin surface 4 ′ by the mold release force F is the largest at the contact interface between the mold 1 and the filling cured resin surface 4 ′, and the central portion of the vertical surface of the filling cured resin surface 4 ′. About twice as much stress is applied as compared with that of the above. This indicates that there is a high possibility that a release crack will occur at the contact interface between the mold 1 and the filled cured resin surface 4 '. In the interface fracture between the mold 1 and the filled cured resin surface 4 ′, a large release force is not required at the time of mold release, and no residual resin is left on the mold 1.

FIG. 5 is a cross section in which the filling cured resin surface 4 ′ forms a convex shape facing outward (90 ° <θ <180 °), and the release force F shown in the figure is applied to the end of the lens blank 3. The progress of the release crack when the load is applied vertically is indicated by a broken line arrow 6 in the figure. The stress distribution applied to the convex filling cured resin surface 4 ′ by the mold release force F is greatest at the contact interface between the mold 1 and the filling cured resin surface 4 ′, and the center of the convex shape of the filling cured resin surface 4 ′. Even when compared with that of the part, a stress of about 5 times or more is concentrated.
This indicates that there is a higher possibility that a release crack will occur at the contact interface between the mold 1 and the filled cured resin surface 4 ′. In the interface fracture between the mold 1 and the filled cured resin surface 4 ′, a large mold release force is not required at the time of mold release, and no residual resin is left on the mold 1.
Furthermore, unlike the mold release process in which the vertical surface of FIG. 4 showing a relatively uniform stress distribution on the filled cured resin surface 4 ′ is formed, the mold release stress is applied between the mold 1 and the filled cured resin surface 4 ′. Since it can concentrate on a contact interface, it can release more efficiently with a small stress.

The above results were obtained through simulations of experiments and structural analysis. Moreover, in each mold release process shown by FIG.3, FIG.4, FIG.5, there exists up-and-down symmetry in both interfaces which become the photocurable resin 2 'after hardening which the shaping | molding die 1 and the lens blank 3 filled.
For this reason, the stress distribution loaded in the photocurable resin 2 ′ after the curing is also symmetrical vertically with the resin center line in between.
However, for the interface between the lens blank 3 and the cured photocurable resin 2 ′, the same stress is applied to the interface between the mold 1 and the cured photocurable resin 2 ′. No cracking occurs because of the close contact treatment.

FIG. 7 is a schematic diagram showing a photo-curing process of replica molding in this configuration.
As described above, the filling cured resin surface 4 in which the uncured photocurable resin 2 pressed and filled between the mold 1 and the lens blank 3 comes into contact with the atmosphere is in an uncured state immediately before light irradiation immediately after filling. A convex shape facing outward is formed.
However, by irradiating light from a light source for photo-curing to the photo-curing resin 2 before curing, the photo-curing resin 2 has an inward curing shrinkage represented by an arrow (↑) shown in the figure. Will occur.
At this time, in order to prevent the convex portion 8 on the mold 1 in this configuration from flowing inward of the photocurable resin 2 due to curing shrinkage, the filled cured resin surface 4 in contact with the atmosphere of the photocurable resin 2. Hardens while retaining its convex shape. For the convex portion 8, the height of the convex portion 8 that can sufficiently prevent the inward flow of the photocurable resin 2 due to curing shrinkage is 70 of the resin thickness of the photocurable resin 2 outside the optical effective diameter. % Or more and 95% or less. That is, if it is 70% or less, the inward flow of the photocurable resin 2 due to curing shrinkage cannot be sufficiently prevented. If it is 95% or more, the distance between the convex portion 8 and the lens blank 3 becomes too narrow, so that a lot of sink marks due to curing shrinkage occur in the portion.

FIG. 8 is a schematic diagram for explaining a release process of replica molding in this configuration. The progress of the release crack when the release force F shown in the figure is applied perpendicularly to the end of the lens blank 3 is indicated by a broken-line arrow 6 in the figure.
As described above, the stress distribution applied to the convex filling cured resin surface 4 ′ by the mold release force F is the largest at the contact interface between the mold 1 and the filling cured resin surface 4 ′. Is likely to occur at the contact interface between the mold 1 and the filled cured resin surface 4 '. In the interface fracture between the mold 1 and the filled cured resin surface 4 ′, a large mold release force is not required at the time of mold release, and no residual resin is left on the mold 1.
From the above, in the present embodiment, by adopting a configuration in which the convex portion is installed at one point or a plurality of points outside the optical effective diameter of the molding die, or the entire outer periphery outside the optical effective diameter. In addition, it becomes possible to improve the releasability between the molding resin and the molding die.

Next, these will be described in more detail.
FIG. 9 is a schematic diagram for explaining a photo-curing process of replica molding using the molding die 1 in which the convex portion 8 is installed at one point outside the optical effective diameter on the molding die surface. a) is a top view thereof, and (b) is a cross-sectional view thereof.
According to such a configuration, as shown in the cross-sectional view of FIG. 9, the filling cured resin surface 4 ′ in the vicinity of the convex shape portion 8 forms a convex shape facing outward, but the convex shape portion 8 is not installed. The filled cured resin surface 4 ′ forms a concave shape facing inward due to curing shrinkage of the molding resin.
FIG. 10 is a schematic diagram for explaining a mold release process of replica molding using a mold in which the convex portion is installed at one point outside the optical effective diameter on the mold surface. Is a top view, and (b) is a cross-sectional view.
The progress of the release crack when the release force F shown in the figure is gradually applied perpendicularly to the entire outer peripheral edge of the lens blank 3 is indicated by a broken line arrow 6 in the figure.
At this time, the same release force F is applied over the entire circumference of the filling and curing resin surface 4 ′, but the mold release crack is caused by the concave filling and curing resin surface 4 from the convex filling and curing resin surface 4 ′ side. 'Proceed to the side. This is due to the fact that the mold release proceeds first at the contact interface between the convex filling cured resin surface 4 ′ and the mold 1 as described above. That is, the contact interface between the convex filling and curing resin surface 4 ′ and the mold 1 is cracked with a weaker release force than the contact interface between the concave filling and curing resin surface 4 ′ and the molding die 1. It is because it can be made.
Similarly, when the convex portion 8 is installed at a plurality of points outside the optical effective diameter of the mold, a concave shape in which the convex portion 8 is not installed from the plurality of convex filling and curing resin surface 4 ′ side. The mold release crack progresses toward the filling cured resin surface 4 ′ side.
Further, in the case where the convex portion 8 is installed in the entire outer periphery outside the optical effective diameter of the mold, there is no release crack from the convex filled cured resin surface 4 ′ in the entire outer periphery toward the center of the mold. proceed.

According to the configuration in which the convex portion according to the present embodiment is installed at one point or a plurality of points outside the optical effective diameter of the molding die, or at the entire outer periphery outside the optical effective diameter, the convex shape portion is installed. It becomes possible to use the point as the starting point of crack progress.
Thereby, since a large mold release force is not required at the time of mold release in replica molding, the mold release property can be improved as compared with the conventional one.
Further, since cohesive failure of the molding resin hardly occurs at the time of mold release in replica molding, production efficiency and cost reduction can be achieved as compared with the conventional one.
Also, according to the composite optical element molded using such a mold, aspherical aberration and chromatic aberration can be corrected better than the conventional optical system, and the entire optical system is small. It is possible to reduce the weight.

Examples of the present invention will be described below.
[Example 1]
In Example 1, a replica forming apparatus for a diffractive optical element used in a copying machine to which the present invention is applied will be described.
FIG. 11 shows a schematic diagram of a replica forming apparatus used for forming a diffractive optical element in the present embodiment.
In FIG. 11, 11 is a mold, 12 is a photocurable resin, 13 is a lens blank, 15 is a light source, 17 is a lens blank holding member, 18 is a convex portion, and 19 is an optical functional shape.

The mold used in the replica molding apparatus of this embodiment includes a reverse shape 19 of a desired optical function shape and a convex portion 18.
The molding die 11 is fixed, and the lens blank 13 is placed on the ring-shaped lens blank holding member 17 into which the molding die 11 is fitted.
Axis alignment between the center axis of the lens blank 13 and the center of the molding surface of the molding die 11 is performed by molding the molding die 11 on the entire circumference of the inner peripheral portion on which the lens blank 13 on the lens blank holding material 17 is placed. A fitting portion having a depth of 1 mm and a width of about 1 mm is provided by combining the center of the surface and the axis.
And it implement | achieves by inserting the outer peripheral part of the lens blank 13 in this fitting part. The lens blank 13 is made of glass or plastic material, and has a flat surface or a curved surface on the optical surface. The ring-shaped lens blank holding member 17 is held so as to be movable up and down.
An appropriate amount of a photocurable resin 12 is supplied onto the molding surface of the molding die 11 by a dispenser (not shown), and an ultraviolet irradiation lamp 15 is disposed above the lens blank 13 with respect to the optical function surface of the molding die 11. Are installed so that they are perpendicularly incident.
As the photocurable resin 12, an optical resin such as an acrylate, a methacrylate, or an epoxy that generates radicals from absorption of a photoinitiator near an ultraviolet wavelength of 365 nm is used.
The ultraviolet irradiation lamp 15 uses a light source having an oscillation peak in the vicinity of a wavelength of 365 nm of a high pressure mercury lamp or an ultrahigh pressure mercury lamp.

FIGS. 12A and 12B are schematic views for explaining the molding die 11 in the present embodiment. FIG. 12A is a top view and FIG. 12B is a cross-sectional view.
The fine shape forming the optical functional surface 19 has a blazed diffraction grating having a grating height of 5 to 20 μm and a grating width of 0.1 to 3 mm on a plane at an optical effective diameter of φ20 mm, as shown in the top view. Concentric with a convex shape toward the center. The convex portions 18 are concentrically arranged in a triangular shape having a height of 40 μm and a width of 100 μm outside the effective optical diameter. The fine shape of the molding surface is formed by a die plating layer cutting method or the like.
FIGS. 13A and 13B are schematic views showing the configuration of a diffractive optical element molded by the mold in Example 1 of the present invention, in which FIG. 13A is a top view and FIG. 13B is a cross-sectional view. In FIG. 13, reference numeral 20 denotes a diffractive optical element manufactured by the molding die 11 in this embodiment, and the optical functional surface 19 ′ of the resin layer formed on the lens blank 13 is directed to the center of the blazed diffraction grating. A concave shape, that is, an inversion shape of the molding die 11 is formed concentrically. Similarly, the convex portion 18 ′ of the resin layer is formed concentrically as the inverted shape of the convex portion 18 in the molding die 11.

Next, the molding process of the diffractive optical element 20 in the present embodiment will be described with reference to FIGS.
First, in FIG. 11, an appropriate amount of the photocurable resin 12 is supplied to the vicinity of the center of the molding surface of the molding die 11 with a dispenser (not shown). And the lens blank 13 which performed the silane coupling process for raising the adhesive force with resin beforehand on one side was provided in the inner periphery on the ring-shaped lens blank holding member 17 with the coupling process surface down. Fit into the fitting part. At this time, a mechanism for holding the lens blank 13, such as a centering chuck or a bell clamp system, may be provided.

Next, as shown in FIG. 14, the ring-shaped lens blank holding member 17 is lowered to bring the molding die 11 and the lens blank 13 relatively close to each other. And it spreads so that the layer thickness of the photocurable resin 12 may be 50 micrometers, and it may fill to the outer periphery of the convex-shaped part 18 outside an optical effective diameter. At this time, the liquid contact speed is adjusted in consideration of the viscosity of the resin and the wettability of the molding surface of the mold in order to prevent air bubbles from being mixed into the photocurable resin 12 and the resin not filled in the molding shape of the mold. Must.
Next, the filled photocurable resin 12 is irradiated with ultraviolet light from the ultraviolet irradiation lamp 15 for 24 J (40 [mW / cm ² ] × 10 minutes). At this time, the filling resin surface 14 in contact with the atmosphere of the photocurable resin 12 forms a convex shape facing outward in an uncured state before the ultraviolet light irradiation. However, during irradiation with ultraviolet light, the filling resin surface 14 has a convex shape because the convex portion 18 on the molding die 11 prevents inward flow due to curing shrinkage of the photocurable resin 12. Cure as it is. About the convex-shaped part 18 in a present Example, as the height of this convex-shaped part 18 which can fully prevent the inward flow by the cure shrinkage of the photocurable resin 12, the photocurable resin 12 outside the optical effective diameter is used. 40 μm, which is 80% height of the layer thickness of 50 μm, was set.
Next, after the polymerization and curing of the photocurable resin 12 is completed, the ring-shaped lens blank holding member 17 is lifted to be composed of the photocurable resin 12 ′ cured from the molding die 11 and the lens blank 13. The diffractive optical element 20 is peeled off. At this time, the release crack progresses from the contact interface between the convex filling cured resin surface 14 on the entire outer periphery of the photocurable resin 12 ′ and the molding die 11 toward the center of the molding die 11, and No residual resin is left on the molding die 11 due to cohesive failure of the resin.
In the present embodiment, the height of the convex portion 18 is set to 40 μm, but the same effect can be obtained as long as it is in the range of 70% to 95% of the layer thickness 50 μm of the photocurable resin 12.

  As described above, according to the present embodiment, since a large release force is not required at the time of mold release in replica molding, the mold release property can be improved as compared with the conventional one. Further, since cohesive failure of the molding resin hardly occurs at the time of mold release in replica molding, production efficiency and cost reduction can be achieved as compared with the conventional one.

[Example 2]
In Example 2, an aspherical lens replica molding apparatus used for a camera lens to which the present invention is applied will be described.
FIG. 15 is a schematic diagram of a replica molding apparatus used for molding an aspheric lens in this example. In FIG. 15, 21 is a mold, 22 is a photocurable resin, 23 is a lens blank, 24 is a filled resin surface, 25 is a light source, 27 is a lens blank holding member, 28 is a convex portion, 29 is an optical function shape, Reference numeral 30 denotes a lens blank butting portion.

The mold used in the replica molding apparatus of the present embodiment includes a reverse shape 29 of a desired optical function shape, a convex shape portion 28, and a lens blank butting portion 30.
The molding die 21 is fixed, and the lens blank 23 is placed on the lens blank butting portion 30 and the lens blank holding member 27 on the molding die 21. The alignment between the lens blank 23 and the molding surface of the molding die 21 is a depth of 300 μm, which is obtained by aligning the molding surface of the molding die 21 with the mounting surface of the lens blank 23 on the lens blank abutting portion 30. A fitting portion of about 1 mm is provided. And it implement | achieves by inserting the outer peripheral part of the lens blank 23 in this fitting part.

  The lens blank 23 is made of a t1 mm × 10 mm × 15 mm flat glass or plastic optical material. The lens blank holding member 27 is held so as to be movable up and down. An appropriate amount of a photocurable resin 22 is supplied onto the molding surface of the molding die 21 by a dispenser (not shown), and an ultraviolet irradiation lamp 25 is disposed above the lens blank 23 with respect to the optical function surface of the molding die 21. Are installed so that they are perpendicularly incident. As the photocurable resin 22, an optical resin such as an acrylate, a methacrylate, or an epoxy that generates radicals from absorption of a photoinitiator near an ultraviolet wavelength of 365 nm is used. The ultraviolet irradiation lamp 25 uses a light source having an oscillation peak in the vicinity of a wavelength of 365 nm of a high pressure mercury lamp or an ultrahigh pressure mercury lamp.

FIG. 16 is a schematic diagram for explaining the molding die 21 in the present embodiment, FIG. 16 (a) is a top view thereof, and FIG. 16 (b) is a sectional view thereof. The optical functional surface 29 has four aspheric lens shapes having a lens diameter of 3 mm and a thickness of 200 to 500 μm arranged on the mold surface.
The convex portion 28 is disposed outside the effective optical diameter so as to cross the molding surface in a semicircular shape having a height of 140 μm and a width of 150 μm. The fine shape of the molding surface is formed by a die plating layer cutting method or the like.
FIG. 17 shows an aspheric lens 31 manufactured by the molding die 21 in this embodiment. The optical functional surface 29 ′ and the convex portion 28 ′ of the resin layer formed on the lens blank 23 are formed as an inverted shape of the molding die 21.

Next, the molding process of the aspheric lens 31 in the present embodiment will be described with reference to FIG.
First, an appropriate amount of the photocurable resin 22 is supplied to the vicinity of the center of the molding surface of the molding die 21 with a dispenser (not shown). Then, a lens blank 23 that has been subjected to a silane coupling process on one side in advance to increase the adhesion to the resin, and a fitting part and a lens provided on the lens blank abutting part 30 with the coupling process side down Place on the blank holding member 27. At this time, the photo-curable resin 22 is spread so as to fill up to the convex portion 28 on the molding surface by the weight of the lens blank 23. However, the layer thickness of the photocurable resin 22 is set to 200 μm with respect to the molding surface by the lens blank abutting portion 30 and the lens blank holding member 27.

Next, the filled photocurable resin 22 is irradiated with 27 J (150 [mW / cm ² ] × 3 minutes) of ultraviolet light from the ultraviolet irradiation lamp 25. At this time, the filling resin surface 24 in contact with the atmosphere of the photocurable resin 22 forms a convex shape facing outward in an uncured state before the ultraviolet light irradiation. However, since the convex portion 28 on the molding die 21 prevents the inward flow due to the curing shrinkage of the photocurable resin 22 at the time of irradiation with ultraviolet light, the filling resin surface 24 maintained a convex shape. Cure as it is. Moreover, about the filling resin surface which does not install this convex-shaped part 28, since the inward flow by hardening shrinkage of the photocurable resin 22 generate | occur | produces, this filling resin surface forms a concave shape. About the convex-shaped part 28 in a present Example, as the height of this convex-shaped part 28 which can fully prevent the inward flow by the cure shrinkage of the photocurable resin 22, the photocurable resin 22 outside the optical effective diameter is used. 140 μm, which is 70% of the layer thickness of 200 μm, was set.

Next, after the polymerization and curing of the photocurable resin 22 is completed, the lens blank holding member 7 is lifted to raise the aspherical lens 31 composed of the photocurable resin 22 cured from the molding die 21 and the lens blank 23. To peel off. At this time, from the contact interface between the convex filling cured resin surface on which the convex portion 28 is disposed and the molding die 21, the concave filling cured resin surface on which the convex portion 28 is not disposed and the molding die 21. The mold release crack progresses toward the contact interface, and no residual resin is left on the molding die 21 due to cohesive failure of the resin.
In the present embodiment, 140 μm is set as the height of the convex portion 28, but the same effect can be obtained as long as it is in the range of 70% to 95% of the layer thickness 200 μm of the photocurable resin 22.

As described above, according to the present embodiment, since a large release force is not required at the time of mold release in replica molding, the mold release property can be improved as compared with the conventional one.
Further, since cohesive failure of the molding resin hardly occurs at the time of mold release in replica molding, production efficiency and cost reduction can be achieved as compared with the conventional one.
Further, by installing the convex portion 28 at an arbitrary position outside the optical effective diameter of the molding die, it is possible to control the progress of the mold release crack in the replica molding.

The schematic diagram for demonstrating the hardening process of the photocurable resin in the replica shaping | molding in embodiment of this invention. The schematic diagram for demonstrating the hardening process of the photocurable resin in the replica shaping | molding in embodiment of this invention. The schematic diagram for demonstrating the mold release process of the replica shaping | molding in embodiment of this invention. The schematic diagram for demonstrating the mold release process of the replica shaping | molding in embodiment of this invention. The schematic diagram for demonstrating the mold release process of the replica shaping | molding in embodiment of this invention. The figure which shows the specific example of the schematic diagram of the mold release process of FIG. 3 by embodiment of this invention. The schematic diagram for demonstrating the hardening process of the photocurable resin in the replica shaping | molding in embodiment of this invention. The schematic diagram for demonstrating the mold release process of the replica shaping | molding in embodiment of this invention. It is a schematic diagram for demonstrating the photocuring process of replica shaping | molding using the shaping | molding die which installed the convex-shaped part in embodiment of this invention in one point outside the optical effective diameter on a shaping | molding die surface, (a) Is a top view, and FIG. It is a schematic diagram for demonstrating the mold release process of replica shaping | molding using the shaping | molding die which installed the convex-shaped part in embodiment of this invention in one point outside the optical effective diameter on a shaping | molding die surface, (a) Is a top view, and FIG. Sectional drawing of the replica shaping | molding apparatus used for shaping | molding of the diffractive optical element in Example 1 of this invention. It is a schematic diagram for demonstrating the shaping | molding die in Example 1 of this invention, (a) is the top view, (b) is sectional drawing. It is a schematic diagram which shows the structure of the diffractive optical element shape | molded with the shaping | molding die in Example 1 of this invention, (a) is the top view, (b) is sectional drawing. Sectional drawing of the replica shaping | molding apparatus used for shaping | molding of the diffractive optical element in Example 1 of this invention. The schematic diagram of the replica shaping | molding apparatus used for shaping | molding of the aspherical lens in Example 2 of this invention. It is a schematic diagram for demonstrating the shaping | molding die in Example 2 of this invention, (a) is the top view, (b) is sectional drawing. It is a schematic diagram which shows the structure of the aspherical lens shape | molded with the shaping | molding die in Example 2 of this invention, (a) is the top view, (b) is sectional drawing.

Explanation of symbols

1: Mold 2: Photocurable resin 2 ′: Photocurable resin 3: Lens blank 4: Filled resin surface 4 ′: Filled cured resin surface 5: Light source 6: Crack release progress 7: Lens blank holding member 8 : Convex part 11: Mold 12: Photocurable resin 12 ': Photocurable resin 13: Lens blank 14: Filling resin surface 15: Light source 17: Lens blank holding member 18: Convex part 18': Convex part 19: Optical functional shape 19 ′: Optical functional shape 20: Diffraction optical element 21: Mold 22: Photocurable resin 22 ′: Photocurable resin 23: Lens blank 24: Filled resin surface 25: Light source 27: Lens blank holding Member 28: Convex shape portion 28 ': Convex shape portion 29: Optical function shape 29': Optical function shape 30: Lens blank butting portion 31: Aspherical lens

Claims (4)

A molding surface for transferring the optical shape to the photocurable resin is provided, the photocurable resin press-filled by the glass substrate on the molding surface is photocured, and the cured resin and the glass substrate are combined with the molding surface. In a mold for molding a composite optical element by releasing more molds,
A mold for molding a composite optical element, comprising a convex portion having a height of 70% or more and 95% or less of the resin thickness of the photocurable resin outside the optically effective molding surface on the molding surface.   2. The composite optical element according to claim 1, wherein the convex portion is provided at one point or a plurality of points outside the optically effective molding surface, or at the entire outer periphery outside the optically effective molding surface. Mold for molding.   A composite optical element, wherein the composite optical element is molded using the molding die for a composite optical element according to claim 1.   The composite optical element according to claim 3, wherein the composite optical element is a diffractive optical element or an aspheric lens.

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